In addition, microbiological studies could provide erroneous or incomplete information. Thus, investigations has showed false-positive results from pneumococcal antigen detection in urine caused by a frequent persistence of positivity after infection or a nasopharyngeal or bronchial colonization. Other authors suggested that community-acquired pneumonia is a polymicrobial infection; consequently, despite the detection of a true microorganism, treatment needs to be also addressed against other potential pathogenic agents.